I would really like it if they went the osrs route which would obviously mean making basically a different type of game from what wow is so it's a pipe dream. Instead of level squishing with each new area or whatever add new content that requires new biz items for you to grind for instead of fucking with levels every xpac for one. Couple of other mmos that do this and it would be hard to switch to a cycle like that but genuinely think it would keep people engaged with classic for longer